// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/base/dragdrop/os_exchange_data_provider_win.h"

#include <stdint.h>

#include <algorithm>

#include "base/files/file_path.h"
#include "base/i18n/file_util_icu.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/pickle.h"
#include "base/strings/utf_string_conversions.h"
#include "base/win/scoped_hglobal.h"
#include "net/base/filename_util.h"
#include "ui/base/clipboard/clipboard.h"
#include "ui/base/clipboard/clipboard_util_win.h"
#include "ui/base/dragdrop/file_info.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/strings/grit/ui_strings.h"
#include "url/gurl.h"

namespace ui {

static const Clipboard::FormatType& GetRendererTaintFormatType()
{
    CR_DEFINE_STATIC_LOCAL(
        Clipboard::FormatType,
        format,
        (ui::Clipboard::GetFormatType("chromium/x-renderer-taint")));
    return format;
}

// Creates a new STGMEDIUM object to hold the specified text. The caller
// owns the resulting object. The "Bytes" version does not NULL terminate, the
// string version does.
static STGMEDIUM* GetStorageForBytes(const void* data, size_t bytes);
template <typename T>
static STGMEDIUM* GetStorageForString(const std::basic_string<T>& data);
// Creates the contents of an Internet Shortcut file for the given URL.
static void GetInternetShortcutFileContents(const GURL& url, std::string* data);
// Creates a valid file name given a suggested title and URL.
static void CreateValidFileNameFromTitle(const GURL& url,
    const base::string16& title,
    base::string16* validated);
// Creates a new STGMEDIUM object to hold a file.
static STGMEDIUM* GetStorageForFileName(const base::FilePath& path);
static STGMEDIUM* GetIDListStorageForFileName(const base::FilePath& path);
// Creates a File Descriptor for the creation of a file to the given URL and
// returns a handle to it.
static STGMEDIUM* GetStorageForFileDescriptor(const base::FilePath& path);

///////////////////////////////////////////////////////////////////////////////
// FormatEtcEnumerator

//
// This object implements an enumeration interface. The existence of an
// implementation of this interface is exposed to clients through
// OSExchangeData's EnumFormatEtc method. Our implementation is nobody's
// business but our own, so it lives in this file.
//
// This Windows API is truly a gem. It wants to be an enumerator but assumes
// some sort of sequential data (why not just use an array?). See comments
// throughout.
//
class FormatEtcEnumerator final : public IEnumFORMATETC {
public:
    FormatEtcEnumerator(DataObjectImpl::StoredData::const_iterator begin,
        DataObjectImpl::StoredData::const_iterator end);
    ~FormatEtcEnumerator();

    // IEnumFORMATETC implementation:
    HRESULT __stdcall Next(ULONG count,
        FORMATETC* elements_array,
        ULONG* elements_fetched) override;
    HRESULT __stdcall Skip(ULONG skip_count) override;
    HRESULT __stdcall Reset() override;
    HRESULT __stdcall Clone(IEnumFORMATETC** clone) override;

    // IUnknown implementation:
    HRESULT __stdcall QueryInterface(const IID& iid, void** object) override;
    ULONG __stdcall AddRef() override;
    ULONG __stdcall Release() override;

private:
    // This can only be called from |CloneFromOther|, since it initializes the
    // contents_ from the other enumerator's contents.
    FormatEtcEnumerator()
        : cursor_(0)
        , ref_count_(0)
    {
    }

    // Clone a new FormatEtc from another instance of this enumeration.
    static FormatEtcEnumerator* CloneFromOther(const FormatEtcEnumerator* other);

private:
    // We are _forced_ to use a vector as our internal data model as Windows'
    // retarded IEnumFORMATETC API assumes a deterministic ordering of elements
    // through methods like Next and Skip. This exposes the underlying data
    // structure to the user. Bah.
    ScopedVector<FORMATETC> contents_;

    // The cursor of the active enumeration - an index into |contents_|.
    size_t cursor_;

    LONG ref_count_;

    DISALLOW_COPY_AND_ASSIGN(FormatEtcEnumerator);
};

// Safely makes a copy of all of the relevant bits of a FORMATETC object.
static void CloneFormatEtc(FORMATETC* source, FORMATETC* clone)
{
    *clone = *source;
    if (source->ptd) {
        source->ptd = static_cast<DVTARGETDEVICE*>(CoTaskMemAlloc(sizeof(DVTARGETDEVICE)));
        *(clone->ptd) = *(source->ptd);
    }
}

FormatEtcEnumerator::FormatEtcEnumerator(
    DataObjectImpl::StoredData::const_iterator start,
    DataObjectImpl::StoredData::const_iterator end)
    : cursor_(0)
    , ref_count_(0)
{
    // Copy FORMATETC data from our source into ourselves.
    while (start != end) {
        FORMATETC* format_etc = new FORMATETC;
        CloneFormatEtc(&(*start)->format_etc, format_etc);
        contents_.push_back(format_etc);
        ++start;
    }
}

FormatEtcEnumerator::~FormatEtcEnumerator()
{
}

STDMETHODIMP FormatEtcEnumerator::Next(
    ULONG count, FORMATETC* elements_array, ULONG* elements_fetched)
{
    // MSDN says |elements_fetched| is allowed to be NULL if count is 1.
    if (!elements_fetched)
        DCHECK_EQ(count, 1ul);

    // This method copies count elements into |elements_array|.
    ULONG index = 0;
    while (cursor_ < contents_.size() && index < count) {
        CloneFormatEtc(contents_[cursor_], &elements_array[index]);
        ++cursor_;
        ++index;
    }
    // The out param is for how many we actually copied.
    if (elements_fetched)
        *elements_fetched = index;

    // If the two don't agree, then we fail.
    return index == count ? S_OK : S_FALSE;
}

STDMETHODIMP FormatEtcEnumerator::Skip(ULONG skip_count)
{
    cursor_ += skip_count;
    // MSDN implies it's OK to leave the enumerator trashed.
    // "Whatever you say, boss"
    return cursor_ <= contents_.size() ? S_OK : S_FALSE;
}

STDMETHODIMP FormatEtcEnumerator::Reset()
{
    cursor_ = 0;
    return S_OK;
}

STDMETHODIMP FormatEtcEnumerator::Clone(IEnumFORMATETC** clone)
{
    // Clone the current enumerator in its exact state, including cursor.
    FormatEtcEnumerator* e = CloneFromOther(this);
    e->AddRef();
    *clone = e;
    return S_OK;
}

STDMETHODIMP FormatEtcEnumerator::QueryInterface(const IID& iid,
    void** object)
{
    *object = NULL;
    if (IsEqualIID(iid, IID_IUnknown) || IsEqualIID(iid, IID_IEnumFORMATETC)) {
        *object = this;
    } else {
        return E_NOINTERFACE;
    }
    AddRef();
    return S_OK;
}

ULONG FormatEtcEnumerator::AddRef()
{
    return InterlockedIncrement(&ref_count_);
}

ULONG FormatEtcEnumerator::Release()
{
    if (InterlockedDecrement(&ref_count_) == 0) {
        ULONG copied_refcnt = ref_count_;
        delete this;
        return copied_refcnt;
    }
    return ref_count_;
}

// static
FormatEtcEnumerator* FormatEtcEnumerator::CloneFromOther(
    const FormatEtcEnumerator* other)
{
    FormatEtcEnumerator* e = new FormatEtcEnumerator;
    // Copy FORMATETC data from our source into ourselves.
    ScopedVector<FORMATETC>::const_iterator start = other->contents_.begin();
    while (start != other->contents_.end()) {
        FORMATETC* format_etc = new FORMATETC;
        CloneFormatEtc(*start, format_etc);
        e->contents_.push_back(format_etc);
        ++start;
    }
    // Carry over
    e->cursor_ = other->cursor_;
    return e;
}

///////////////////////////////////////////////////////////////////////////////
// OSExchangeDataProviderWin, public:

// static
bool OSExchangeDataProviderWin::HasPlainTextURL(IDataObject* source)
{
    base::string16 plain_text;
    return (ClipboardUtil::GetPlainText(source, &plain_text) && !plain_text.empty() && GURL(plain_text).is_valid());
}

// static
bool OSExchangeDataProviderWin::GetPlainTextURL(IDataObject* source,
    GURL* url)
{
    base::string16 plain_text;
    if (ClipboardUtil::GetPlainText(source, &plain_text) && !plain_text.empty()) {
        GURL gurl(plain_text);
        if (gurl.is_valid()) {
            *url = gurl;
            return true;
        }
    }
    return false;
}

// static
DataObjectImpl* OSExchangeDataProviderWin::GetDataObjectImpl(
    const OSExchangeData& data)
{
    return static_cast<const OSExchangeDataProviderWin*>(&data.provider())->data_.get();
}

// static
IDataObject* OSExchangeDataProviderWin::GetIDataObject(
    const OSExchangeData& data)
{
    return static_cast<const OSExchangeDataProviderWin*>(&data.provider())->data_object();
}

// static
IDataObjectAsyncCapability* OSExchangeDataProviderWin::GetIAsyncOperation(
    const OSExchangeData& data)
{
    return static_cast<const OSExchangeDataProviderWin*>(&data.provider())->async_operation();
}

OSExchangeDataProviderWin::OSExchangeDataProviderWin(IDataObject* source)
    : data_(new DataObjectImpl())
    , source_object_(source)
{
}

OSExchangeDataProviderWin::OSExchangeDataProviderWin()
    : data_(new DataObjectImpl())
    , source_object_(data_.get())
{
}

OSExchangeDataProviderWin::~OSExchangeDataProviderWin()
{
}

OSExchangeData::Provider* OSExchangeDataProviderWin::Clone() const
{
    return new OSExchangeDataProviderWin(data_object());
}

void OSExchangeDataProviderWin::MarkOriginatedFromRenderer()
{
    STGMEDIUM* storage = GetStorageForString(std::string());
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        GetRendererTaintFormatType().ToFormatEtc(), storage));
}

bool OSExchangeDataProviderWin::DidOriginateFromRenderer() const
{
    return HasCustomFormat(GetRendererTaintFormatType());
}

void OSExchangeDataProviderWin::SetString(const base::string16& data)
{
    STGMEDIUM* storage = GetStorageForString(data);
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        Clipboard::GetPlainTextWFormatType().ToFormatEtc(), storage));

    // Also add the UTF8-encoded version.
    storage = GetStorageForString(base::UTF16ToUTF8(data));
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        Clipboard::GetPlainTextFormatType().ToFormatEtc(), storage));
}

void OSExchangeDataProviderWin::SetURL(const GURL& url,
    const base::string16& title)
{
    // NOTE WELL:
    // Every time you change the order of the first two CLIPFORMATS that get
    // added here, you need to update the EnumerationViaCOM test case in
    // the _unittest.cc file to reflect the new arrangement otherwise that test
    // will fail! It assumes an insertion order.

    // Add text/x-moz-url for drags from Firefox
    base::string16 x_moz_url_str = base::UTF8ToUTF16(url.spec());
    x_moz_url_str += '\n';
    x_moz_url_str += title;
    STGMEDIUM* storage = GetStorageForString(x_moz_url_str);
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        Clipboard::GetMozUrlFormatType().ToFormatEtc(), storage));

    // Add a .URL shortcut file for dragging to Explorer.
    base::string16 valid_file_name;
    CreateValidFileNameFromTitle(url, title, &valid_file_name);
    std::string shortcut_url_file_contents;
    GetInternetShortcutFileContents(url, &shortcut_url_file_contents);
    SetFileContents(base::FilePath(valid_file_name), shortcut_url_file_contents);

    // Add a UniformResourceLocator link for apps like IE and Word.
    storage = GetStorageForString(base::UTF8ToUTF16(url.spec()));
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        Clipboard::GetUrlWFormatType().ToFormatEtc(), storage));
    storage = GetStorageForString(url.spec());
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        Clipboard::GetUrlFormatType().ToFormatEtc(), storage));

    // TODO(beng): add CF_HTML.
    // http://code.google.com/p/chromium/issues/detail?id=6767

    // Also add text representations (these should be last since they're the
    // least preferable).
    SetString(base::UTF8ToUTF16(url.spec()));
}

void OSExchangeDataProviderWin::SetFilename(const base::FilePath& path)
{
    STGMEDIUM* storage = GetStorageForFileName(path);
    DataObjectImpl::StoredDataInfo* info = new DataObjectImpl::StoredDataInfo(
        Clipboard::GetCFHDropFormatType().ToFormatEtc(), storage);
    data_->contents_.push_back(info);

    storage = GetIDListStorageForFileName(path);
    if (!storage)
        return;
    info = new DataObjectImpl::StoredDataInfo(
        Clipboard::GetIDListFormatType().ToFormatEtc(), storage);
    data_->contents_.push_back(info);
}

void OSExchangeDataProviderWin::SetFilenames(
    const std::vector<FileInfo>& filenames)
{
    for (size_t i = 0; i < filenames.size(); ++i) {
        STGMEDIUM* storage = GetStorageForFileName(filenames[i].path);
        DataObjectImpl::StoredDataInfo* info = new DataObjectImpl::StoredDataInfo(
            Clipboard::GetCFHDropFormatType().ToFormatEtc(), storage);
        data_->contents_.push_back(info);
    }
}

void OSExchangeDataProviderWin::SetPickledData(
    const Clipboard::FormatType& format,
    const base::Pickle& data)
{
    STGMEDIUM* storage = GetStorageForBytes(data.data(), data.size());
    data_->contents_.push_back(
        new DataObjectImpl::StoredDataInfo(format.ToFormatEtc(), storage));
}

void OSExchangeDataProviderWin::SetFileContents(
    const base::FilePath& filename,
    const std::string& file_contents)
{
    // Add CFSTR_FILEDESCRIPTOR
    STGMEDIUM* storage = GetStorageForFileDescriptor(filename);
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        Clipboard::GetFileDescriptorFormatType().ToFormatEtc(), storage));

    // Add CFSTR_FILECONTENTS
    storage = GetStorageForBytes(file_contents.data(), file_contents.length());
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        Clipboard::GetFileContentZeroFormatType().ToFormatEtc(), storage));
}

void OSExchangeDataProviderWin::SetHtml(const base::string16& html,
    const GURL& base_url)
{
    // Add both MS CF_HTML and text/html format.  CF_HTML should be in utf-8.
    std::string utf8_html = base::UTF16ToUTF8(html);
    std::string url = base_url.is_valid() ? base_url.spec() : std::string();

    std::string cf_html = ClipboardUtil::HtmlToCFHtml(utf8_html, url);
    STGMEDIUM* storage = GetStorageForBytes(cf_html.c_str(), cf_html.size());
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        Clipboard::GetHtmlFormatType().ToFormatEtc(), storage));

    STGMEDIUM* storage_plain = GetStorageForBytes(utf8_html.c_str(),
        utf8_html.size());
    data_->contents_.push_back(new DataObjectImpl::StoredDataInfo(
        Clipboard::GetTextHtmlFormatType().ToFormatEtc(), storage_plain));
}

bool OSExchangeDataProviderWin::GetString(base::string16* data) const
{
    return ClipboardUtil::GetPlainText(source_object_.get(), data);
}

bool OSExchangeDataProviderWin::GetURLAndTitle(
    OSExchangeData::FilenameToURLPolicy policy,
    GURL* url,
    base::string16* title) const
{
    base::string16 url_str;
    bool success = ClipboardUtil::GetUrl(
        source_object_.get(), url, title,
        policy == OSExchangeData::CONVERT_FILENAMES ? true : false);
    if (success) {
        DCHECK(url->is_valid());
        return true;
    } else if (GetPlainTextURL(source_object_.get(), url)) {
        if (url->is_valid())
            *title = net::GetSuggestedFilename(*url, "", "", "", "", std::string());
        else
            title->clear();
        return true;
    }
    return false;
}

bool OSExchangeDataProviderWin::GetFilename(base::FilePath* path) const
{
    std::vector<base::string16> filenames;
    bool success = ClipboardUtil::GetFilenames(source_object_.get(), &filenames);
    if (success)
        *path = base::FilePath(filenames[0]);
    return success;
}

bool OSExchangeDataProviderWin::GetFilenames(
    std::vector<FileInfo>* filenames) const
{
    std::vector<base::string16> filenames_local;
    bool success = ClipboardUtil::GetFilenames(source_object_.get(), &filenames_local);
    if (success) {
        for (size_t i = 0; i < filenames_local.size(); ++i)
            filenames->push_back(
                FileInfo(base::FilePath(filenames_local[i]), base::FilePath()));
    }
    return success;
}

bool OSExchangeDataProviderWin::GetPickledData(
    const Clipboard::FormatType& format,
    base::Pickle* data) const
{
    DCHECK(data);
    bool success = false;
    STGMEDIUM medium;
    FORMATETC format_etc = format.ToFormatEtc();
    if (SUCCEEDED(source_object_->GetData(&format_etc, &medium))) {
        if (medium.tymed & TYMED_HGLOBAL) {
            base::win::ScopedHGlobal<char*> c_data(medium.hGlobal);
            DCHECK_GT(c_data.Size(), 0u);
            *data = base::Pickle(c_data.get(), static_cast<int>(c_data.Size()));
            success = true;
        }
        ReleaseStgMedium(&medium);
    }
    return success;
}

bool OSExchangeDataProviderWin::GetFileContents(
    base::FilePath* filename,
    std::string* file_contents) const
{
    base::string16 filename_str;
    if (!ClipboardUtil::GetFileContents(source_object_.get(), &filename_str,
            file_contents)) {
        return false;
    }
    *filename = base::FilePath(filename_str);
    return true;
}

bool OSExchangeDataProviderWin::GetHtml(base::string16* html,
    GURL* base_url) const
{
    std::string url;
    bool success = ClipboardUtil::GetHtml(source_object_.get(), html, &url);
    if (success)
        *base_url = GURL(url);
    return success;
}

bool OSExchangeDataProviderWin::HasString() const
{
    return ClipboardUtil::HasPlainText(source_object_.get());
}

bool OSExchangeDataProviderWin::HasURL(
    OSExchangeData::FilenameToURLPolicy policy) const
{
    return (ClipboardUtil::HasUrl(
                source_object_.get(),
                policy == OSExchangeData::CONVERT_FILENAMES ? true : false)
        || HasPlainTextURL(source_object_.get()));
}

bool OSExchangeDataProviderWin::HasFile() const
{
    return ClipboardUtil::HasFilenames(source_object_.get());
}

bool OSExchangeDataProviderWin::HasFileContents() const
{
    return ClipboardUtil::HasFileContents(source_object_.get());
}

bool OSExchangeDataProviderWin::HasHtml() const
{
    return ClipboardUtil::HasHtml(source_object_.get());
}

bool OSExchangeDataProviderWin::HasCustomFormat(
    const Clipboard::FormatType& format) const
{
    FORMATETC format_etc = format.ToFormatEtc();
    return (source_object_->QueryGetData(&format_etc) == S_OK);
}

void OSExchangeDataProviderWin::SetDownloadFileInfo(
    const OSExchangeData::DownloadFileInfo& download)
{
    // If the filename is not provided, set storage to NULL to indicate that
    // the delay rendering will be used.
    // TODO(dcheng): Is it actually possible for filename to be empty here? I
    // think we always synthesize one in WebContentsDragWin.
    STGMEDIUM* storage = NULL;
    if (!download.filename.empty())
        storage = GetStorageForFileName(download.filename);

    // Add CF_HDROP.
    DataObjectImpl::StoredDataInfo* info = new DataObjectImpl::StoredDataInfo(
        Clipboard::GetCFHDropFormatType().ToFormatEtc(), storage);
    info->downloader = download.downloader;
    data_->contents_.push_back(info);

    // Adding a download file always enables async mode.
    data_->SetAsyncMode(VARIANT_TRUE);
}

void OSExchangeDataProviderWin::SetDragImage(
    const gfx::ImageSkia& image,
    const gfx::Vector2d& cursor_offset)
{
    drag_image_ = image;
    drag_image_offset_ = cursor_offset;
}

const gfx::ImageSkia& OSExchangeDataProviderWin::GetDragImage() const
{
    return drag_image_;
}

const gfx::Vector2d& OSExchangeDataProviderWin::GetDragImageOffset() const
{
    return drag_image_offset_;
}

///////////////////////////////////////////////////////////////////////////////
// DataObjectImpl, IDataObject implementation:

// The following function, DuplicateMedium, is derived from WCDataObject.cpp
// in the WebKit source code. This is the license information for the file:
/*
 * Copyright (C) 2007 Apple Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
static void DuplicateMedium(CLIPFORMAT source_clipformat,
    STGMEDIUM* source,
    STGMEDIUM* destination)
{
    switch (source->tymed) {
    case TYMED_HGLOBAL:
        destination->hGlobal = static_cast<HGLOBAL>(OleDuplicateData(
            source->hGlobal, source_clipformat, 0));
        break;
    case TYMED_MFPICT:
        destination->hMetaFilePict = static_cast<HMETAFILEPICT>(OleDuplicateData(
            source->hMetaFilePict, source_clipformat, 0));
        break;
    case TYMED_GDI:
        destination->hBitmap = static_cast<HBITMAP>(OleDuplicateData(
            source->hBitmap, source_clipformat, 0));
        break;
    case TYMED_ENHMF:
        destination->hEnhMetaFile = static_cast<HENHMETAFILE>(OleDuplicateData(
            source->hEnhMetaFile, source_clipformat, 0));
        break;
    case TYMED_FILE:
        destination->lpszFileName = static_cast<LPOLESTR>(OleDuplicateData(
            source->lpszFileName, source_clipformat, 0));
        break;
    case TYMED_ISTREAM:
        destination->pstm = source->pstm;
        destination->pstm->AddRef();
        break;
    case TYMED_ISTORAGE:
        destination->pstg = source->pstg;
        destination->pstg->AddRef();
        break;
    }

    destination->tymed = source->tymed;
    destination->pUnkForRelease = source->pUnkForRelease;
    if (destination->pUnkForRelease)
        destination->pUnkForRelease->AddRef();
}

DataObjectImpl::StoredDataInfo::StoredDataInfo(const FORMATETC& format_etc,
    STGMEDIUM* medium)
    : format_etc(format_etc)
    , medium(medium)
    , owns_medium(true)
{
}

DataObjectImpl::StoredDataInfo::~StoredDataInfo()
{
    if (owns_medium) {
        ReleaseStgMedium(medium);
        delete medium;
    }
    if (downloader.get())
        downloader->Stop();
}

DataObjectImpl::DataObjectImpl()
    : is_aborting_(false)
    , in_drag_loop_(false)
    , in_async_mode_(false)
    , async_operation_started_(false)
    , observer_(NULL)
{
}

DataObjectImpl::~DataObjectImpl()
{
    StopDownloads();
    if (observer_)
        observer_->OnDataObjectDisposed();
}

void DataObjectImpl::StopDownloads()
{
    for (StoredData::iterator iter = contents_.begin();
         iter != contents_.end(); ++iter) {
        if ((*iter)->downloader.get()) {
            (*iter)->downloader->Stop();
            (*iter)->downloader = 0;
        }
    }
}

void DataObjectImpl::RemoveData(const FORMATETC& format)
{
    if (format.ptd)
        return; // Don't attempt to compare target devices.

    for (StoredData::iterator i = contents_.begin(); i != contents_.end(); ++i) {
        if (!(*i)->format_etc.ptd && format.cfFormat == (*i)->format_etc.cfFormat && format.dwAspect == (*i)->format_etc.dwAspect && format.lindex == (*i)->format_etc.lindex && format.tymed == (*i)->format_etc.tymed) {
            contents_.erase(i);
            return;
        }
    }
}

void DataObjectImpl::OnDownloadCompleted(const base::FilePath& file_path)
{
    DataObjectImpl::StoredData::iterator iter = contents_.begin();
    for (; iter != contents_.end(); ++iter) {
        if ((*iter)->format_etc.cfFormat == CF_HDROP) {
            // Release the old storage.
            if ((*iter)->owns_medium) {
                ReleaseStgMedium((*iter)->medium);
                delete (*iter)->medium;
            }

            // Update the storage.
            (*iter)->owns_medium = true;
            (*iter)->medium = GetStorageForFileName(file_path);

            break;
        }
    }
    DCHECK(iter != contents_.end());
}

void DataObjectImpl::OnDownloadAborted()
{
}

HRESULT DataObjectImpl::GetData(FORMATETC* format_etc, STGMEDIUM* medium)
{
    if (is_aborting_)
        return DV_E_FORMATETC;

    StoredData::iterator iter = contents_.begin();
    while (iter != contents_.end()) {
        if ((*iter)->format_etc.cfFormat == format_etc->cfFormat && (*iter)->format_etc.lindex == format_etc->lindex && ((*iter)->format_etc.tymed & format_etc->tymed)) {
            // If medium is NULL, delay-rendering will be used.
            if ((*iter)->medium) {
                DuplicateMedium((*iter)->format_etc.cfFormat, (*iter)->medium, medium);
            } else {
                // Fail all GetData() attempts for DownloadURL data if the drag and drop
                // operation is still in progress.
                if (in_drag_loop_)
                    return DV_E_FORMATETC;

                bool wait_for_data = false;

                // In async mode, we do not want to start waiting for the data before
                // the async operation is started. This is because we want to postpone
                // until Shell kicks off a background thread to do the work so that
                // we do not block the UI thread.
                if (!in_async_mode_ || async_operation_started_)
                    wait_for_data = true;

                if (!wait_for_data)
                    return DV_E_FORMATETC;

                // Notify the observer we start waiting for the data. This gives
                // an observer a chance to end the drag and drop.
                if (observer_)
                    observer_->OnWaitForData();

                // Now we can start the download.
                if ((*iter)->downloader.get()) {
                    (*iter)->downloader->Start(this);
                    if (!(*iter)->downloader->Wait()) {
                        is_aborting_ = true;
                        return DV_E_FORMATETC;
                    }
                }

                // The stored data should have been updated with the final version.
                // So we just need to call this function again to retrieve it.
                return GetData(format_etc, medium);
            }
            return S_OK;
        }
        ++iter;
    }

    return DV_E_FORMATETC;
}

HRESULT DataObjectImpl::GetDataHere(FORMATETC* format_etc,
    STGMEDIUM* medium)
{
    return DATA_E_FORMATETC;
}

HRESULT DataObjectImpl::QueryGetData(FORMATETC* format_etc)
{
    StoredData::const_iterator iter = contents_.begin();
    while (iter != contents_.end()) {
        if ((*iter)->format_etc.cfFormat == format_etc->cfFormat)
            return S_OK;
        ++iter;
    }
    return DV_E_FORMATETC;
}

HRESULT DataObjectImpl::GetCanonicalFormatEtc(
    FORMATETC* format_etc, FORMATETC* result)
{
    format_etc->ptd = NULL;
    return E_NOTIMPL;
}

HRESULT DataObjectImpl::SetData(
    FORMATETC* format_etc, STGMEDIUM* medium, BOOL should_release)
{
    RemoveData(*format_etc);

    STGMEDIUM* local_medium = new STGMEDIUM;
    if (should_release) {
        *local_medium = *medium;
    } else {
        DuplicateMedium(format_etc->cfFormat, medium, local_medium);
    }

    DataObjectImpl::StoredDataInfo* info = new DataObjectImpl::StoredDataInfo(*format_etc, local_medium);
    info->medium->tymed = format_etc->tymed;
    info->owns_medium = !!should_release;
    // Make newly added data appear first.
    // TODO(dcheng): Make various setters agree whether elements should be
    // prioritized from front to back or back to front.
    contents_.insert(contents_.begin(), info);

    return S_OK;
}

HRESULT DataObjectImpl::EnumFormatEtc(
    DWORD direction, IEnumFORMATETC** enumerator)
{
    if (direction == DATADIR_GET) {
        FormatEtcEnumerator* e = new FormatEtcEnumerator(contents_.begin(), contents_.end());
        e->AddRef();
        *enumerator = e;
        return S_OK;
    }
    return E_NOTIMPL;
}

HRESULT DataObjectImpl::DAdvise(
    FORMATETC* format_etc, DWORD advf, IAdviseSink* sink, DWORD* connection)
{
    return OLE_E_ADVISENOTSUPPORTED;
}

HRESULT DataObjectImpl::DUnadvise(DWORD connection)
{
    return OLE_E_ADVISENOTSUPPORTED;
}

HRESULT DataObjectImpl::EnumDAdvise(IEnumSTATDATA** enumerator)
{
    return OLE_E_ADVISENOTSUPPORTED;
}

///////////////////////////////////////////////////////////////////////////////
// DataObjectImpl, IDataObjectAsyncCapability implementation:

HRESULT DataObjectImpl::EndOperation(
    HRESULT result, IBindCtx* reserved, DWORD effects)
{
    async_operation_started_ = false;
    return S_OK;
}

HRESULT DataObjectImpl::GetAsyncMode(BOOL* is_op_async)
{
    *is_op_async = in_async_mode_ ? VARIANT_TRUE : VARIANT_FALSE;
    return S_OK;
}

HRESULT DataObjectImpl::InOperation(BOOL* in_async_op)
{
    *in_async_op = async_operation_started_ ? VARIANT_TRUE : VARIANT_FALSE;
    return S_OK;
}

HRESULT DataObjectImpl::SetAsyncMode(BOOL do_op_async)
{
    in_async_mode_ = !!do_op_async;
    return S_OK;
}

HRESULT DataObjectImpl::StartOperation(IBindCtx* reserved)
{
    async_operation_started_ = true;
    return S_OK;
}

///////////////////////////////////////////////////////////////////////////////
// DataObjectImpl, IUnknown implementation:

HRESULT DataObjectImpl::QueryInterface(const IID& iid, void** object)
{
    if (!object)
        return E_POINTER;
    if (IsEqualIID(iid, IID_IDataObject) || IsEqualIID(iid, IID_IUnknown)) {
        *object = static_cast<IDataObject*>(this);
    } else if (in_async_mode_ && IsEqualIID(iid, __uuidof(IDataObjectAsyncCapability))) {
        *object = static_cast<IDataObjectAsyncCapability*>(this);
    } else {
        *object = NULL;
        return E_NOINTERFACE;
    }
    AddRef();
    return S_OK;
}

ULONG DataObjectImpl::AddRef()
{
    base::RefCountedThreadSafe<DownloadFileObserver>::AddRef();
    return 0;
}

ULONG DataObjectImpl::Release()
{
    base::RefCountedThreadSafe<DownloadFileObserver>::Release();
    return 0;
}

///////////////////////////////////////////////////////////////////////////////
// DataObjectImpl, private:

static STGMEDIUM* GetStorageForBytes(const void* data, size_t bytes)
{
    HANDLE handle = GlobalAlloc(GPTR, static_cast<int>(bytes));
    if (handle) {
        base::win::ScopedHGlobal<uint8_t*> scoped(handle);
        memcpy(scoped.get(), data, bytes);
    }

    STGMEDIUM* storage = new STGMEDIUM;
    storage->hGlobal = handle;
    storage->tymed = TYMED_HGLOBAL;
    storage->pUnkForRelease = NULL;
    return storage;
}

template <typename T>
static STGMEDIUM* GetStorageForString(const std::basic_string<T>& data)
{
    return GetStorageForBytes(
        data.c_str(),
        (data.size() + 1) * sizeof(typename std::basic_string<T>::value_type));
}

static void GetInternetShortcutFileContents(const GURL& url,
    std::string* data)
{
    DCHECK(data);
    static const std::string kInternetShortcutFileStart = "[InternetShortcut]\r\nURL=";
    static const std::string kInternetShortcutFileEnd = "\r\n";
    *data = kInternetShortcutFileStart + url.spec() + kInternetShortcutFileEnd;
}

static void CreateValidFileNameFromTitle(const GURL& url,
    const base::string16& title,
    base::string16* validated)
{
    if (title.empty()) {
        if (url.is_valid()) {
            *validated = net::GetSuggestedFilename(url, "", "", "", "",
                std::string());
        } else {
            // Nothing else can be done, just use a default.
            *validated = l10n_util::GetStringUTF16(IDS_APP_UNTITLED_SHORTCUT_FILE_NAME);
        }
    } else {
        *validated = title;
        base::i18n::ReplaceIllegalCharactersInPath(validated, '-');
    }
    static const wchar_t extension[] = L".url";
    static const size_t max_length = MAX_PATH - arraysize(extension);
    if (validated->size() > max_length)
        validated->erase(max_length);
    *validated += extension;
}

static STGMEDIUM* GetStorageForFileName(const base::FilePath& path)
{
    const size_t kDropSize = sizeof(DROPFILES);
    const size_t kTotalBytes = kDropSize + (path.value().length() + 2) * sizeof(wchar_t);
    HANDLE hdata = GlobalAlloc(GMEM_MOVEABLE, kTotalBytes);

    base::win::ScopedHGlobal<DROPFILES*> locked_mem(hdata);
    DROPFILES* drop_files = locked_mem.get();
    drop_files->pFiles = sizeof(DROPFILES);
    drop_files->fWide = TRUE;
    wchar_t* data = reinterpret_cast<wchar_t*>(
        reinterpret_cast<BYTE*>(drop_files) + kDropSize);
    const size_t copy_size = (path.value().length() + 1) * sizeof(wchar_t);
    memcpy(data, path.value().c_str(), copy_size);
    data[path.value().length() + 1] = L'\0'; // Double NULL

    STGMEDIUM* storage = new STGMEDIUM;
    storage->tymed = TYMED_HGLOBAL;
    storage->hGlobal = hdata;
    storage->pUnkForRelease = NULL;
    return storage;
}

static LPITEMIDLIST PIDLNext(LPITEMIDLIST pidl)
{
    return reinterpret_cast<LPITEMIDLIST>(
        reinterpret_cast<BYTE*>(pidl) + pidl->mkid.cb);
}

static size_t PIDLSize(LPITEMIDLIST pidl)
{
    size_t s = 0;
    while (pidl->mkid.cb > 0) {
        s += pidl->mkid.cb;
        pidl = PIDLNext(pidl);
    }
    // We add 2 because an LPITEMIDLIST is terminated by two NULL bytes.
    return 2 + s;
}

static LPITEMIDLIST GetNthPIDL(CIDA* cida, int n)
{
    return reinterpret_cast<LPITEMIDLIST>(
        reinterpret_cast<LPBYTE>(cida) + cida->aoffset[n]);
}

static LPITEMIDLIST GetPidlFromPath(const base::FilePath& path)
{
    LPITEMIDLIST pidl = NULL;
    LPSHELLFOLDER desktop_folder = NULL;
    LPWSTR path_str = const_cast<LPWSTR>(path.value().c_str());

    if (FAILED(SHGetDesktopFolder(&desktop_folder)))
        return NULL;

    HRESULT hr = desktop_folder->ParseDisplayName(
        NULL, NULL, path_str, NULL, &pidl, NULL);

    return SUCCEEDED(hr) ? pidl : NULL;
}

static STGMEDIUM* GetIDListStorageForFileName(const base::FilePath& path)
{
    LPITEMIDLIST pidl = GetPidlFromPath(path);
    if (!pidl)
        return NULL;

    // When using CFSTR_SHELLIDLIST the hGlobal field of the STGMEDIUM is a
    // pointer to a CIDA*. A CIDA is a variable length struct that contains a PIDL
    // count (a UINT), an array of offsets of the following PIDLs (a UINT[]) and
    // then a series of PIDLs laid out contiguously in memory. A PIDL is
    // represented by an ITEMIDLIST struct, which contains a single SHITEMID.
    // Despite only containing a single SHITEMID, ITEMIDLISTs are so-named because
    // SHITEMIDs contain their own size and so given one, the next can be found by
    // looking at the section of memory after it. The end of a list is indicated
    // by two NULL bytes.
    // Here we require two PIDLs - the first PIDL is the parent folder and is
    // NULL here to indicate that the parent folder is the desktop, and the second
    // is the PIDL of |path|.
    const size_t kPIDLCountSize = sizeof(UINT);
    const size_t kPIDLOffsetsSize = 2 * sizeof(UINT);
    const size_t kFirstPIDLOffset = kPIDLCountSize + kPIDLOffsetsSize;
    const size_t kFirstPIDLSize = 2; // Empty PIDL - 2 NULL bytes.
    const size_t kSecondPIDLSize = PIDLSize(pidl);
    const size_t kCIDASize = kFirstPIDLOffset + kFirstPIDLSize + kSecondPIDLSize;
    HANDLE hdata = GlobalAlloc(GMEM_MOVEABLE, kCIDASize);

    base::win::ScopedHGlobal<CIDA*> locked_mem(hdata);
    CIDA* cida = locked_mem.get();
    cida->cidl = 1; // We have one PIDL (not including the 0th root PIDL).
    cida->aoffset[0] = kFirstPIDLOffset;
    cida->aoffset[1] = kFirstPIDLOffset + kFirstPIDLSize;
    LPITEMIDLIST idl = GetNthPIDL(cida, 0);
    idl->mkid.cb = 0;
    idl->mkid.abID[0] = 0;
    idl = GetNthPIDL(cida, 1);
    memcpy(idl, pidl, kSecondPIDLSize);

    STGMEDIUM* storage = new STGMEDIUM;
    storage->tymed = TYMED_HGLOBAL;
    storage->hGlobal = hdata;
    storage->pUnkForRelease = NULL;
    return storage;
}

static STGMEDIUM* GetStorageForFileDescriptor(
    const base::FilePath& path)
{
    base::string16 file_name = path.value();
    DCHECK(!file_name.empty());
    HANDLE hdata = GlobalAlloc(GPTR, sizeof(FILEGROUPDESCRIPTOR));
    base::win::ScopedHGlobal<FILEGROUPDESCRIPTOR*> locked_mem(hdata);

    FILEGROUPDESCRIPTOR* descriptor = locked_mem.get();
    descriptor->cItems = 1;
    descriptor->fgd[0].dwFlags = FD_LINKUI;
    wcsncpy_s(descriptor->fgd[0].cFileName, MAX_PATH, file_name.c_str(),
        std::min(file_name.size(), static_cast<size_t>(MAX_PATH - 1u)));

    STGMEDIUM* storage = new STGMEDIUM;
    storage->tymed = TYMED_HGLOBAL;
    storage->hGlobal = hdata;
    storage->pUnkForRelease = NULL;
    return storage;
}

///////////////////////////////////////////////////////////////////////////////
// OSExchangeData, public:

// static
OSExchangeData::Provider* OSExchangeData::CreateProvider()
{
    return new OSExchangeDataProviderWin();
}

} // namespace ui
